Locking nut assembly for a cone crusher

ABSTRACT

A two-piece locking nut assembly for securing a mantle to a head assembly of a cone crusher. The two-piece locking nut assembly includes an inner nut and an outer nut. The inner nut includes a set of axial bores that each receive a jackscrew. Once the locking nut assembly is in position on the head assembly, the series of jackscrews are tightened to exert a force on the mantle that is counteracted by forces through the inner nut and into the head to create a locking force between the locking nut assembly and the head assembly. The outer nut is turned along the inner nut to hold the locking nut assembly in place. Once the outer nut is moved into position, the jackscrews are removed such that the outer nut continues to apply the locking force between the mantle and the head through the locking nut assembly.

BACKGROUND OF TUE INVENTION

The present disclosure generally relates to rock crushing equipment.More specifically, the present disclosure relates to a locking nutassembly for use with a cone crusher that facilitates installationand/or replacement of mantles on the head assembly of the cone crusher.

Presently, rock crushing systems, such as those referred to as conecrushers, generally break apart rock, stone or other material in acrushing cavity between a stationary element and a moving element. Forexample, a conical rock crusher is comprised of a head assemblyincluding a crushing head that gyrates about a vertical axis within astationary bowl supported by the adjustment ring of the rock crusher.The crushing head assembly surrounds an eccentric that rotates about afixed shaft to impart the gyrational movement of the crushing headassembly which crushes rock, stone or other material in a crushing gapbetween a mantle on the crushing head assembly and a bowl liner on thebowl assembly.

The exterior of the conical head assembly is covered with a protectivewear-resistant mantle that engages the material that is being crushed,such as rock, stone, mineral or other substances. During use of the conecrusher, the mantle resists the wear imparted through the crushingaction of the cone crusher. After a period of use, a worn mantle can beremoved and replaced with a new mantle.

Typically, a locking nut is used to forcibly secure the mantle to thecrushing head assembly by applying a large downward force on the top ofthe mantle. The locking nut includes an internally threaded surface thatengages an externally threaded surface on the head assembly. Inconventional crushers, downward force is applied to the mantle byscrewing down the internally threaded locking nut on the mating threadsof the externally threaded head assembly. The turning effort istypically applied by a special wrench having a protruding arm. The largeamount of turning effort that is needed to tighten down the locking nutoften requires the use of difficult mechanical operations to create thesufficient locking force to adequately secure the mantle on the headassembly.

SUMMARY OF THE INVENTION

The present disclosure generally relates to a method and system forsecuring a mantle to a head assembly of rock crushing equipment. Morespecifically, the present disclosure relates to a locking nut assemblyfor use with a cone crusher that allows the connection of a mantle tothe head assembly of the cone crusher.

The locking nut assembly of the present disclosure includes an inner nutthat has a threaded inner surface, a threaded outer surface and a seriesof axial bores that extend from an annular top face to an annular bottomface of the inner nut. The threaded outer surface of the annular innernut receives a corresponding series of threads formed along an innersurface of an outer nut. The threaded interaction between the inner andouter nuts allows the outer nut to move relative to the inner nut uponrotation of the outer nut relative to the inner nut.

The series of axial bores formed in the inner nut receive acorresponding series of jackscrews. Each jackscrew includes a threadedportion that is received in a threaded section of the annular bore. Thethreaded interaction between the annular bores of the inner nut and thejackscrews allow the jackscrews to be rotated and moved relative to theinner nut.

In some embodiments of locking nut assembly, during initial assembly theinner and outer nuts are staged relative to each other before the stagedcombination is positioned on the head assembly. In one configuration,the outer nut is supported on blocks and the inner nut is positionedwithin the outer nut and turned down as far as possible with respect tothe outer nut.

In another alternate configuration, the inner nut could be supported andthe outer nut turned down along the inner nut. In each of theseconfigurations, the inner and outer nuts are staged relative to eachother before installation.

Once the inner and outer nuts are staged relative to each other, thecombination of the inner and outer nuts is positioned such that theinner threads of the inner nut engage a threaded portion of the headassembly. In one contemplated embodiment, the inner nut is turned downon the threaded portion of the head assembly until a jackscrew exitsurface of the inner nut engages a torch ring positioned on the mantle.In an alternate embodiment, the inner nut is turned down along thethreaded portion of the head assembly only far enough to leave a smallspace or gap between the jackscrew exit surface and the torch ring.

Although a torch ring is used in several embodiments of the disclosure,it is contemplated that the torch ring could be eliminated. In such anembodiment, the inner nut is turned down until the inner nut eitherengages the mantle directly or is spaced slightly above the mantle.

After the inner nut is moved into the desired position, each of the setof jackscrews are installed in an axial bore. In the embodimentincluding a conventional torch ring, the jackscrews are each rotateduntil a contact end of each of the jackscrews contacts the torch ring.Each jackscrew is rotated further such that the torch ring is moved awayfrom the inner nut and the set of jackscrews combine to exert a downwardforce on the torch ring which is opposed by the reactionary lockingforce between the inner nut and the head assembly. Preferably, thejackscrews are tightened incrementally in a star pattern to exert anevenly applied downward force on the mantle. In the contemplatedembodiment in which the torch ring is eliminated, the jackscrews contactthe mantle directly.

Once the jackscrews are properly torqued, the outer nut is rotated onthe threaded interface with the inner nut until the bottom face surfaceof the outer nut engages the torch ring. When the bottom face surfaceengages the torch ring, the outer nut is in the proper holding position.In the contemplated embodiment in which the torch ring is eliminated,the outer nut is rotated into direct contact with the mantle.

Once the outer nut is in the proper holding position, each of thejackscrews can be removed such that the outer nut holds the locking nutassembly in place. Preferably, the jackscrews are removed in anincremental star pattern to avoid creating overloads on the lastjackscrews to be removed. The jackscrews are removed from the inner nutto avoid damage that can occur to the jackscrews during use of thecrusher. The relatively small area of surface contact between thejackscrews and the torch ring can damage the jackscrews if thejackscrews are left in place during operation of the crusher. When theouter nut is in the proper position and the jackscrews removed, thereactionary locking force is now created by the outer nut rather thanthe jackscrews. In this manner, the jackscrews arc inserted to createthe locking force and removed once the outer nut is tightened down intocontact with the torch ring or mantle.

Various other features, objects and advantages of the invention will bemade apparent from the following description taken together with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carryingout the disclosure. In the drawings:

FIG. 1 is a partial section view of a cone crusher including the lockingnut assembly of the present disclosure;

FIG. 2 is an exploded perspective view of the locking nut assembly;

FIG. 3 is a perspective, assembled view of the inner and outer nuts withthe jackscrews installed;

FIG. 4 is a partial section view of the locking nut assembly prior toinstallation on the head assembly of the cone crusher;

FIG. 5 is a partial section view illustrating the initial position ofthe locking nut assembly on the head assembly;

FIG. 6 is a partial section view illustrating the position of thejackscrews within the inner nut of the locking nut assembly;

FIG. 7 is a partial section view illustrating the tightening of thejackscrews to create the locking force;

FIG. 8 is a partial section view illustrating the downward movement ofthe outer nut along the inner nut and into contact with the torch ring;

FIG. 9 is a partial section view illustrating the removal of thejackscrews;

FIG. 10 is a partial section view illustrating the installation of boththe cover plate and the feed plate to the locking nut assembly;

FIG. 11 is a section view of an alternate embodiment of the mantle andlocking nut assembly; and

FIG. 12 is a section view of another alternate embodiment of the mantleand locking nut assembly.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a cone crusher 10 that is operable to crush material,such as rock, stone, or mineral or other substances. The cone crusher 10includes a mainframe 12 having a lower flange 14. The cone crusher 10can be any size rock crusher or include any type of crusher mantle.Lower flange 14 rests upon a platform-like foundation that can includeconcrete piers (not shown), a foundation block, a steel platform orother supporting member. A central hub 16 of the mainframe 12 includesan upwardly diverging tapered bore 18. The bore 18 is adapted to receivea main shaft 20.

An eccentric 22 surrounds the main shaft 20 and is coupled to a headassembly 24. The eccentric 22 rotates about the main shaft 20, therebycausing the head assembly 24 to gyrate within the cone crusher 10.Gyration of the head assembly 24 within a bowl 26 allows rock, stone,ore, minerals or other materials to be crushed between a mantle 30 and abowl liner 32. The mantle 30 is a removable component that is held inplace on the head assembly 24 by a locking nut assembly 34 of thepresent disclosure. The locking nut assembly 34 in the embodiment shownreceives a feed plate 28 that can also be replaced when worn.

As can be understood in FIG. 1, when the cone crusher 10 is operating,countershaft 36 rotates the eccentric 22 through the interaction betweena pinion 38 and a gear 40. The rotation of the eccentric 22 creates thegyrational movement of the head assembly 24 within the stationary bowl26. The gyrational movement of the head assembly 24 allows the materialto be crushed to enter into the crushing gap 42. Further rotation of theeccentric 22 reduces the crushing gap 42 on this material and forcefullyfractures some of the particles being crushed by the cone crusher 10.The cone crusher 10 can be one of many different types of cone crushersavailable from various manufacturers, such as Metso Minerals ofMilwaukee, Wis. As an example, the cone crusher 10 shown in FIG. 1 canbe an MP® series rock crusher, such as the MP800, MP1000 and MP1250available from Metso Minerals Industries. Inc. However, different typesof cone crushers could be utilized while operating within the scope ofthe present disclosure.

Although the locking nut assembly 34 is shown in the drawing figures asbeing used with a cone crusher, it is contemplated by the inventors thatthe concept of the present disclosure could be extended to other typesof cone crushers and possibly used for the installation of mantles onthe main shafts of gyratory crushers. The design concept could beextended to other types of crushers that use locking bolts instead oflocking nuts to hold the replaceable mantle in place along a headassembly.

During operation of the cone crusher 10 with the material being crushed,the crushing forces created in the crushing gap 42 exert a force againstthe mantle 30 of the head assembly 24. As illustrated in FIG. 1, themantle 30 is a removable component of the cone crusher 10 such that themantle 30 can be replaced when worn. In addition, the bowl liner 32 isalso a removable component that can be removed and replaced when worn.

As can be understood in FIG. 1, the mantle 30 rests upon a sloped outersurface 44 of the head assembly 24. The mantle 30 is securely held inposition along the outer surface 44 by the locking nut assembly 34 ofthe present disclosure. The locking nut assembly 34 is received on anupper attachment portion 46 of the head assembly 24 in a manner thatwill be described in greater detail below. The locking nut assembly 34receives the feed plate 28 which protects the locking nut assembly 34from incoming material to be crushed. The feed plate 28 can be removedand replaced as required.

FIGS. 2 and 3 illustrate the locking nut assembly 34 of the presentdisclosure. As shown in FIG. 2, the locking nut assembly 34 generallyincludes an inner nut 48, an outer nut 50 and a set of jackscrews 52.When the locking nut assembly 34 is in the assembled condition of FIG.3, the inner nut 48 is received within the outer nut 50 and each of thejackscrews 52 are received in one of a set of axial bores 54 formed inthe inner nut 48.

Referring now to FIGS. 2 and 4, the inner nut 48 generally includes amain body 56 that has a generally annular shape. The main body 56extends from a top face surface 58 to a bottom face surface 60. Theinner nut 48 includes an outer surface 61 having a first series ofthreads 62. The first series of threads 62 extends along the outersurface 61 from the top face surface 58 to a lower shoulder 64. In theembodiment shown in FIG. 2, the lower shoulder 64 is spaced from thebottom face surface 60.

The inner nut 48 further includes a second series of threads 66 that areformed along an inner surface 68 of the inner nut 48. The second seriesof threads 66 extends along the inner surface 68 from a location nearthe top face surface 58 to the bottom face surface 60. As illustrated inFIGS. 2 and 4, the inner surface 68 defines an annular opening 70 thatis sized to receive the attachment portion 46 of the head assembly 24.When the locking nut assembly is used on a crusher that uses a lockingbolt rather than a locking nut to hold the mantle in place along thehead assembly, the inner nut will be configured differently such thatthe second series of threads engage internal threads of the headassembly. Thus, it should be understood that the locking nut assemblyshown and described could be reconfigured to be a locking bolt such thatthe assembly of the present disclosure can be used on different types ofcrushers.

Referring back to FIG. 2, the inner nut 48 includes a series of axialbores 54 that each extend through the main body 56 of the inner nut 48from the top face surface 58. As shown in FIG. 4, each of the axialbores 54 includes an upper portion 72 and a threaded lower portion 74.In the embodiment shown in FIG. 4, the threaded lower portion 74terminates at a lower opening 76 that is formed in a jackscrew exitsurface 78 of the inner nut 48. The jackscrew exit surface 78 isrecessed slightly from the bottom face surface 60 and is defined by ashoulder 80. In an alternate embodiment, the axial bore 54 could bethreaded along its entire length.

Referring back to FIGS. 2 and 3, the locking nut assembly 34 furtherincludes the outer nut 50. The outer nut 50 extends from a top facesurface 82 to a bottom face surface 84. In the embodiment shown in FIGS.2-11, the top face surface 82 is formed as part of an attachment flange86 that extends outward past the outer surface 88 of the lower portion89. However, in contemplated alternate embodiments, the attachmentflange 86 could be eliminated from the outer nut 50, as shown in thealternate configuration of FIG. 12.

The inner surface 90 of the outer nut 50 includes a series of threads 92formed along at least a portion of the inner surface 90. The series ofthreads 92 on the outer nut 50 are configured to interact with the firstseries of threads 62 formed on the outer surface of the inner nut 48. Ascan be understood in FIGS. 3 and 4, the threaded interaction between thefirst series of threads 62 formed on the outer surface of the inner nut48 and the series of threads 92 formed along the inner surface 90 of theouter nut allows for relative movement between the inner and outer nuts48, 50 upon rotation of either component. As will be described in detailbelow, when the inner nut 48 is stationary and the outer nut 50 rotated,the outer nut 50 will move either upward or downward relative to theinner nut 48 depending upon the direction of rotation of the outer nut50.

Referring back to FIG. 2, the locking nut assembly 34 further includes aset of jackscrews 52 that are each received within one of the axialbores 54. Each of the jackscrews 52 includes a threaded portion 96, anunthreaded shank 98, an engagement end 100 and a contact end 102.Although the embodiment shown includes an unthreaded shank 98, it iscontemplated that the threads could extend along the entire length ofthe jackscrew 52. The engagement end 100 is configured in the embodimentshown in FIG. 2 as having a series of flat side surfaces such that theengagement end 100 can receive a wrench socket for rotating thejackscrew 52. The contact end 102 includes a generally flat bottomsurface 104. In the embodiment shown in FIG. 2, each of the jackscrews52 is formed from machined steel such that the jackscrews 52 have therequired strength for exerting relatively large forces on the mantle,possibly through a torch ring of the cone crusher without excessivedeformation.

As shown in FIG. 2, in the embodiment of the locking nut assembly 34illustrated, the locking nut assembly 34 includes twenty jackscrews 52spaced around the main body of the inner nut 48. In the embodimentillustrated, the jackscrews are grouped in four groups of fivejackscrews, where each group of jackscrews is centered at 90° intervalsaround the annular inner nut 48. Although this configuration of thejackscrews 52 is shown in the preferred embodiment, it should beunderstood that a different number of jackscrews 52 could be used orthat the jackscrews 52 could be located in other configurations whileoperating within the scope of the present disclosure. Although otherconfigurations of the jackscrews 52 are contemplated, it is desirablethat the jackscrews be spaced around the entire circumference of theinner nut such that the combination of the spaced jackscrews 52 willexert a relatively uniform force when the jackscrews are individuallytightened in the manner to be described below.

Referring now to FIG. 4, in the embodiment illustrated, the lowerportion 74 of each axial bore 54 includes a series of threads thatengage the external threads formed on the threaded portion 96 of thejackscrew 52 (see FIG. 2). Thus, rotation of the jackscrew 52 within theaxial bore 54 causes the jackscrew to move relative to the inner nut 48.

In the embodiment shown in FIG. 4, the locking nut assembly 34 furtherincludes a torch ring 106. The torch ring 106 is positioned on a top rim108 of the mantle 30. The torch ring 106 provides a surface 110 forcontact with the inner nut 48, the jackscrews 52 and the outer nut 50 aswill be described in greater detail below. The expendable torch ring 106is typically destroyed during removal of a worn mantle and is replacedwhen a new mantle is installed.

Referring now to FIGS. 4-10, the sequence of operation required toutilize the locking nut assembly 34 of the present disclosure to securethe mantle 30 to the head assembly 24 will now be described. Referringfirst to FIG. 4, before the locking nut assembly 34 is installed ontothe head assembly 24, the inner and outer nuts 48, 50 are initiallystaged relative to each other. In a first implementation of the stagingprocess, the outer nut 50 is supported on blocks. Once the outer nut 50is supported, the inner nut 48 is positioned within the open interioruntil the external threads of the inner nut engage the internal threadsof the outer nut. The inner nut 48 is then turned down along the outernut 50 until the jackscrew exit surface 78 of the inner nut reaches theelevation of the bottom face surface 84.

If the inner and outer nuts 48, 50 have different configurations thanshown in FIGS. 4-10, such as shown in FIG. 12, the staging sequence maybe altered or even eliminated. To stage the embodiment shown in FIG. 12,the inner nut 48 is supported on blocks and the outer nut 50 turned downalong the inner nut 48. Alternatively, the inner nut 48 shown in FIG. 12could be initially attached to the head assembly and the outer nut 50turned down the inner nut 48.

Once the inner and outer nuts 48, 50 have been staged as shown in FIG.4, the mantle 30 and torch ring 106 are positioned on the head assembly24. After the new mantle 30 and torch ring 106 are positioned, thestaged locking nut assembly 34 is positioned in alignment with theattachment portion 46 of the head assembly 24. Once positioned as shownin FIG. 4, the locking nut assembly 34 is lowered until the threads 66formed along the inner surface 68 of the inner nut 48 engage theexternal threads 94 formed on the attachment portion 46 of the headassembly 24. Once the threads engage, the combination of the inner andouter nuts are turned down along the attachment portion 46 until thejackscrew exit surface 78 of the inner nut 48 engages the top surface110 of the torch ring 106, as illustrated in FIG. 5. When the jackscrewexit surface 78 of the inner nut 48 engages the top surface 110 of thetorch ring 106, the bottom face surface 84 of the outer nut 50 is spacedfrom the top surface 110 by a gap 112. The gap 112 allows forconfirmation that the inner nut 48 has properly seated on the torch ring106. In the embodiment shown in FIGS. 4 and 5, the combination of theinner and outer nuts, 48, 50 are manually turned down the attachmentportion 46 through use of a pry bar used in conjunction with partfeatures and accessories.

Referring now to FIG. 6, once the inner nut 48 is turned down intocontact with the top surface 110 of the torch ring 106, the set ofjackscrews 52 are each inserted into the axial bores 54. Each of thejackscrews 52 is then rotated within the axial bore 54 until the contactend 102 engages the top surface 110 of the torch ring 106.

Once the contact end 102 engages the top surface 110 of the torch ring106, each of the jackscrews is torqued using a mechanical tighteningdevice. In the preferred embodiment of the disclosure, the series ofjackscrews are preferentially incrementally tightened in a star pattern,similar to tensioning lug nuts on an automobile wheel. As anillustrative example, the jackscrews shown in FIG. 2 are grouped intofour groups, each group having five jackscrews. The groups can belabeled A, B, C and D, with A opposite B, and each jackscrew in therespective group numbered 1-5 in a consistent direction around thelocking nut assembly 34. During initial tightening, the jackscrews aretightened in the sequence A1, B1, C1, D1/A2, B2, C2, D2/A3, B3, C3, D3,etc.

After all of the jackscrews are initially tightened, an operator repeatsthe sequence above to tighten the jackscrews to a final tension. As eachof the jackscrews 52 are torqued, the jackscrews 52 push the mantledownward with the torch ring, creating or increasing a gap 114 shown inFIG. 7 between the jackscrew exit surface 78 of the inner nut 48 and thetop surface 110 of the torch ring 106.

As the jackscrews are torqued, the gap 112 between the bottom facesurface 84 of the outer nut 50 and the top surface 110 of the torch ring106 also increases, as can be seen in the comparison between FIGS. 6 and7. The continued torquing of each of the jackscrews 52 creates a lockingforce that is seen between the threads 62 formed along the inner surface68 of the inner nut 48 and the external threads formed on the attachmentportion 46 of the head assembly 24. As can be understood in FIG. 7, thesummed forces of the jackscrews 52 create the total locking force ratherthan the need to rotate the entire locking nut assembly 34 about theattachment portion 46 of the head assembly 24.

Once the jackscrews 52 have been properly tightened, the outer nut 50 isrotated relative to the inner nut 48 until the bottom face surface 84contacts the top surface 110 of the torch ring 106, as shown in FIG. 8.The outer nut 50 can be turned down along the inner nut 48 using manydifferent mechanisms. However, it is contemplated that since thejackscrews 52 create the required locking force, the outer nut 50 can beturned down by hand using a pry bar and associated accessories until thebottom face surface 84 contacts the top surface 110 of the torch ring106.

Once the bottom face surface 84 of the outer nut 50 contacts the topsurface 110 of the torch ring 106, each of the jackscrews 52 can beremoved from the inner nut 48, as can be seen in a comparison betweenFIGS. 8 and 9. Preferably, the jackscrews are removed in the incrementalstar pattern described above to avoid any overloads on the lastjackscrews to be removed. When the jackscrews 52 are removed, most orall of the locking force between the attachment portion 46 of the headassembly 24 and the inner nut 48 is maintained by the contact betweenthe outer nut 50 and the torch ring 106. As illustrated in FIG. 9, thegap 114 remains between the jackscrew exit surface 78 and the topsurface 110 once the outer nut 50 has been turned down into the positionshown in FIG. 9. Thus, the outer nut 50 maintains the locking forcecreated by applying a small torque to each of the set of jackscrews 52without requiring a large torque being applied to either the inner nut48 or the outer nut 50.

Once the locking nut assembly is in position to hold the mantle on thehead assembly, a head lift plate (not shown) is attached to the innernut. The head lift plate includes a lift eye or a hoist ring that allowsthe entire head assembly with the installed mantle and locknut assemblyto be lifted and inserted into the crusher.

Once the entire head assembly is in position within the crusher, thehead lift plate is removed and a cover plate 116 can be attached to thetop face surface 58 of the inner nut 48 to cover the series of axialbores 54, as shown in FIG. 10. The cover plate 116 prevents debris fromentering into the axial bores 54 during use of the crusher.

Once the cover plate 116 has been installed, a feed plate 118 can beattached to the outer nut 50 through a series of threaded fasteners 121.As described previously, the feed plate 118 is a wear protection devicethat can be removed and replaced when needed.

FIG. 11 illustrates an alternate embodiment of the locking nut assemblyof the present disclosure. In the alternate embodiment shown in FIG. 11,the mantle 30 includes an engagement portion 122 that protrudesinwardly. The engagement portion 122 is positioned beneath each of theaxial bores 54 formed in the inner nut 48 such that when the jackscrews(not shown) are received in the axial bores 54 and tightened, thecontact end of each jackscrew contacts the engagement portion 122.During the installation of the locking nut assembly, the inner nut 48 isturned down only far enough until a small gap exists between the bottomface surface 123 and the top surface 125 of the engagement portion 122of the mantle 30. The small gap will reduce the probable tendency forbinding to occur at the bottom face surface 123 at disassembly forinstallation of a new mantle. The gap will reduce the cutting requiredto remove a worn mantle. In the embodiment shown in FIG. 11, the innernut 48 does not include the recessed jackscrew exit surface as in theembodiment of FIGS. 4-10. Instead, each of the axial bores 54 extendsthrough the bottom face surface 123.

After the jackscrews are tightened in the same manner previouslydescribed, the outer nut 50 is turned down along the inner nut 48 untilthe bottom face surface 84 contacts the torch ring 124. The torch ring124 is received in a groove formed in the mantle 30. The locking nutassembly functions in the same way as described previously except thatthe jackscrews engage the mantle 30 directly, rather than the torchring.

FIG. 12 illustrates another alternate embodiment of the locking nutassembly of the present disclosure. In the embodiment shown in FIG. 12,the mantle 30 includes an engagement portion 130 that protrudes radiallyinward. The engagement portion 130 is positioned beneath each of theaxial bores 54 formed in the inner nut 48 such that when the jackscrews(not shown) are received in the axial bores 54, the contact end of eachjackscrew contacts a top surface 132 of the engagement portion 130.

After the series of jackscrews are tightened in the same mannerpreviously described, the outer nut 50 is turned down along the innernut 48 until the bottom face surface 84 contacts the top surface 132 ofthe mantle 30. The torch ring 124 shown in FIG. 11 is eliminated in theembodiment of FIG. 12 such that both the jackscrews and the outer nut 50contact the top surface 132 of the mantle 30 directly. The two-piecelocking nut functions in the same way as described previously exceptthat the jackscrews and the outer nut 50 engage the mantle 30 directly.It is contemplated that the inner nut 48 is turned down only far enoughuntil a small gap exists between the jackscrew exit surface 78 and thetop surface 132 of the mantle 30. The initial gap will reduce theprobable tendency for binding to occur at the jackscrew exit surface atdisassembly for installation of a new mantle. The gap will reduce thecutting required to remove a worn mantle 30.

In the embodiment shown in FIG. 12, the outer nut 50 does not include anattachment flange 86, as was the case in the embodiment of FIG. 4.Instead, the outer nut 50 includes a notch 134 formed in the outersurface 136. The notch 134 provides access to an open shaft 138 thatextends through the top surface 140. The top surface 140, in turn,receives a feed plate 142. The feed plate 142 includes a series ofrecessed regions 144 that each receive the head of a threaded fastener(not shown) such that the feed plate 142 can be securely attached to theouter nut 50.

1. A locking nut assembly, comprising: an inner nut having a firstseries of threads, a second series of threads and a plurality of axialbores extending through the inner nut; an outer nut having a threadedinner surface in threaded engagement with the first series of threads ofthe inner nut such that the outer nut is movable along the inner nut;and a plurality of jackscrews each received in one of the axial bores ofthe inner nut.
 2. The locking nut assembly of claim 1 wherein each ofthe axial bores includes a threaded portion that receives externalthreads formed on each of the jackscrews such that each of thejackscrews are movable relative to the inner nut by rotating thejackscrew.
 3. The locking nut assembly of claim 1 wherein the axialbores are spaced around the annular top face of the inner nut.
 4. Thelocking nut assembly of claim 3 wherein the plurality of axial bores areeach located between an inner surface and an outer surface of the innernut.
 5. A locking nut assembly for use with a cone crusher having a headassembly and a mantle, the locking nut assembly comprising: an inner nuthaving a threaded inner surface, a threaded outer surface and aplurality of axial bores that each extend through the inner nut, whereinthe threaded inner surface is configured to be received on the headassembly; an outer nut having a threaded inner surface in threadedengagement with the threaded outer surface of the inner nut such thatthe outer nut is movable along the inner nut; and a plurality ofjackscrews that are each threadedly received in one of the axial boresof the inner nut such that the jackscrews are movable relative to theinner nut.
 6. The locking nut assembly of claim 5 wherein the outer nutis movable along the inner nut upon rotation of the outer nut when theinner nut is received on the head assembly.
 7. The locking nut assemblyof claim 6 further comprising a torch ring positioned between the mantleand the inner and outer nuts, wherein the jackscrews and the outer nutare independently movable into contact with the torch ring to exert alocking force on the mantle when the inner nut is received on the headassembly.
 8. The locking nut assembly of claim 6 wherein the jackscrewsand the outer nut are independently movable relative to the inner nut toexert a locking force on the mantle when the inner nut is received onthe head assembly.
 9. The locking nut assembly of claim 6 furthercomprising a torch ring positioned on a portion of the mantle, whereinthe jackscrews are movable into contact with the mantle and the outernut is movable into contact with the torch ring.
 10. The locking nutassembly of claim 5 wherein each of the axial bores includes a threadedportion that receives external threads on one of the jackscrews.
 11. Thelocking nut assembly of claim 5 wherein the axial bores are spacedaround the annular top face of the inner nut.
 12. A method of securing amantle to a head assembly of a cone crusher, comprising: providing alocking nut assembly having an inner nut having a plurality of axialbores and an outer nut that is movable relative to the inner nut;attaching the inner nut of the locking nut assembly to the head assemblyof the crusher; inserting a plurality of jackscrews into the axial boresof the inner nut; moving the plurality of jackscrews relative to theinner nut such that the jackscrews create a locking force between thelocking nut assembly and the head assembly; moving the outer nut alongthe inner nut until the outer nut exerts a force on the mantle; andmoving the plurality of jackscrews away from the mantle such that theouter nut exerts the locking force.
 13. The method of claim 12 furthercomprising the step of removing the jackscrews from the inner nut. 14.The method of claim 12 wherein a torch ring is positioned on the mantleand both the plurality of jackscrews and the outer nut engage the torchring.
 15. The method of claim 12 wherein each of the axial boresincludes a series of internal threads that engage external threads oneach of the jackscrews, wherein the jackscrews are each rotated relativeto the inner nut to move the jackscrews to create the locking force. 16.The method of claim 12 wherein the inner nut includes a threaded outersurface that engages a threaded inner surface of the outer nut, whereinthe outer nut is rotated relative to the inner nut to move the outer nutto engage the mantle.
 17. The method of claim 12 wherein the inner nutincludes a threaded inner surface that engages a threaded outer surfaceof the head assembly, wherein the locking force secures the inner nut tothe head assembly.
 18. The method of claim 12 wherein the step ofattaching the inner nut of the locking nut assembly to the head assemblyof the crusher includes rotating the inner nut relative to the headassembly to move the inner nut toward a torch ring positioned on themantle.
 19. The method of claim 18 wherein the inner nut of the lockingnut assembly is moved into engagement with the torch ring prior to theplurality of jackscrews creating a locking force between the locking nutassembly and the head assembly.